1. Field of the Invention
The present invention relates to a memory card authentication system, a memory card host device, a memory card, a storage area switching method, and a storage area switching program, which are capable of switching plural storage areas.
2. Description of the Related Art
A memory card containing a rewritable nonvolatile memory, which does not lose information saved therein even if the power supply is turned off, is a storage device for saving digital information for devices for controlling digital information, such as a digital camera, a portable music player or a personal digital assistant (such a device will be hereinafter referred to as a “memory card host device”). The memory card host device manages data on a memory with a file system such as FAT 16. The FAT 16 file system defines a cluster address in 16 bits; accordingly, assuming that a cluster size is equal to 32 kilobytes, the file system can achieve a maximum area of 2 gigabytes.
Meanwhile, a storage capacity per memory card is increasing due to advances in the memory manufacturing technology, mounting technology, and the like.
There are disclosed technologies related to memory cards, namely, a recording device which physically loads two memory cards in order to increase storage capacity (Japanese Patent Application Laid-open No. 2001-325127), a memory card which incorporates a protection switch and a protection circuit in order to protect writing (Japanese Patent Application Laid-open No. 62(1987)-179037), and the like.
A file system has a limit in terms of storage area capacity for handling. Accordingly, a conventional memory card host device which does not correspond to the switching of storage areas, has problems in that the data managed by the changed storage areas cannot be handled by changing the storage area within the memory card.